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Bent valve?


Scrapson

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Sounds good hainz I’ll just put it together moderately right and if it brakes just put it together again I’ll get it right eventually that’s what happens when your 16 and don’t listen to anyone till you mess up. 

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Ya know part of me feels like that’s bull shit but either way I’ll take it. Youtube does make it a hell of a lot easier but there isn’t much for L20B mostly the old guy here in scio that used to rally race them is the guy I go to for tips for more power otherwise he just tells me just figure it out look it up or “fuck I don’t remember I’m too old for this”

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10 hours ago, Scrapson said:

Is there any sort of precaution I should do since it was decked so much. I talked to 2 mechanics and they said it should be fine but I feel like something catastrophic is going to happen.

 

Stock L20B compression is 8.4. Removing 0.012" or 0.3048mm makes the combustion chamber just 1.728cc smaller and the compression is now just under 8.6 or about the same as the L16. 

 

Stock valve lift on an L20B is 0.413". You can run a cam that lifts the valves to 0.480". You can't go higher because the spring will stack not that you can't go to higher lift. An extra 0.012" is nothing to worry about.

 

Will it affect cam timing? If this was a high strung high HP engine it might but stock engines are very forgiving. In theory it should advance cam timing but I doubt it's measurable and besides the L series has a built in adjustment for worn timing chains and sprockets.  

 

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Awesome thank you mike for reassuring me that my next paycheck isn’t going down the shitter.yet. Anyways. If I were to put a little spicier of a cam in (I am not touching it I’ll take it to someone else) should I be worried for a valve and piston intercourse?

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11 hours ago, datzenmike said:

 

Stock L20B compression is 8.4. Removing 0.012" or 0.3048mm makes the combustion chamber just 1.728cc smaller and the compression is now just under 8.6 or about the same as the L16. 

 

Stock valve lift on an L20B is 0.413". You can run a cam that lifts the valves to 0.480". You can't go higher because the spring will stack not that you can't go to higher lift. An extra 0.012" is nothing to worry about.

 

Will it affect cam timing? If this was a high strung high HP engine it might but stock engines are very forgiving. In theory it should advance cam timing but I doubt it's measurable and besides the L series has a built in adjustment for worn timing chains and sprockets.  

 

 

 Keep in mind that when the piston is at the top of it's stroke and closest the valves they are closed and out of harm's way on the compression stroke and on the exhaust stroke the exhaust is almost closed and the intake just beginning to open.

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20 hours ago, Scrapson said:

gerwaiian... anyways so I’ll put the intake and exhuast on but I swear to god if it has vacuum leak again from the intake manifold I’m going to just drive it and say fuck it. I got the intake manifold checked and the intake port checked on the head they were both straight not warped or twisted. Honestly no idea what’s going on there. 

Tightening the manifolds has to be done sort of like a head gasket. Work back and forth from top to bottom and don't tighten one before the other. If you get it clamped down evenly, it should not have any vacuum or water leaks at all.

 

I actually use a torque wrench on everything. Swapping from bolts to studs will help the process too by eliminating the possibility of stripping an aluminum thread out of the cylinder head. They help align the gasket and manifolds too, making installation easier.

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Mine has studs with nuts and washers that clamp it down but i can never get the bottom far right bolt tightened all the way but I was going to just put a longer stud in for that one. I don't know how many ft-lbs it has to be I had assumed 1 and a half ugga dugga for that. (which is approximately 30 ft-lbs or something like that)\

 

1 Ugga Dugga 20 FT-LBS

2 Ugga Dugga 40 FT-LBS

3 Ugga Dugga 80 FT-LBS

1 I think I broke my hand Too Many FT-LBS *stop there its tight enough*

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thats a lot less than i thought I just went till they were tight then a little extra to prevent leakage. I gotta get a clicking torque wrench then I only have an old school one.

I'll put it on tonight then since I am over the 12mpg in the van maybe Ill even try to start it (send prayers)

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